1. Field of the Invention
The present invention relates to the production of shaped articles of titanium dioxide, and, more especially, to the production of a particular titanium dioxide well suited for shaping operations.
2. Description of the Prior Art
At the present time, in certain industrial processes, such as, for example, the denitriding and/or desulfurization of flue gases, the Claus process for the production of elemental sulfur, and the like, catalysts based on titanium dioxide are preferably employed. Furthermore, these catalysts are used in the form of a bed in columns. Whatever their form, it should limit the loss of catalyst charged. Thus, these catalysts are most typically produced by shaping a powder thereof, for example by molding, extrusion, or the like.
However, these TiO.sub.2 catalysts must also have good mechanical properties, to prevent wear by attrition. In addition, they must have good impact strength and a porosity or specific surface to provide high catalytic efficiency.
EP 38,741 describes a process for the shaping of titanium dioxide to provide articles having good mechanical properties and having adequate porosity for their use as catalysts or catalyst supports.
Moreover, such titanium dioxide suitable for shaping is produced by the hydrolysis of a solution of titanium sulfate, or a solution obtained by the sulfuric acid decomposition of ilmenite.
The titanium dioxides produced by the hydrolysis of another titanium compound, such as titanium oxychloride, cannot be used to shape articles having good mechanical properties and a specific surface or porosity sufficient to be used for catalysis.
For example, Japanese Patent No. 53/095,893 indicates that the titanium dioxide produced by the hydrolysis of titanium chloride cannot be formed.